aclfilter.java

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package jaoso.framework.web.filter;

import jaoso.framework.context.Global;

import jaoso.framework.security.Acl;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;


/**
 * DOCUMENT ME!
 *
 * @author $author$
 * @version $Revision$
 */
public class AclFilter implements Filter {

    //~ Instance fields ========================================================

    /** Acl DAO, responsible for reading acl configuration from file */
    private Acl acl;

    /**
     * The filter configuration object we are associated with.  If this value
     * is null, this filter instance is not currently configured.
     */
    private FilterConfig config;

    /** DOCUMENT ME! */
    private Log log = LogFactory.getLog(AclFilter.class);

    //~ Methods ================================================================

    /**
     * Take this filter out of service.
     */
    public final void destroy() {

        config = null;
        acl = null;
    }

    /**
     * Use acl-config.xml to store web pages that can only be viewed by logined
     * user. For every web resource, if it is a protected resource, check if
     * the user has been logined, if not, save corrent page to session,
     * forward to logon page
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param chain The filter chain we are processing
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public final void doFilter(final ServletRequest request,
        final ServletResponse response, final FilterChain chain)
        throws IOException, ServletException {

        HttpServletRequest hreq = (HttpServletRequest) request;
        String[] urls = StringUtils.split(hreq.getRequestURI(), "/");
        String url = urls[(urls.length - 1)];
        log.info("filter url: " + url);
        boolean noLogin = (hreq.getSession(false) == null)
            || (hreq.getSession(false)
                    .getAttribute("account") == null)
            || (hreq.getSession(false)
                    .getAttribute("group") == null);

        //check login
        if (noLogin && acl.isProtectedResource(url)) {

            // String url = "/" + uri + "?" + hreq.getQueryString();
            //hreq.setAttribute( ForumConstants.DEST_URL, url );
            config.getServletContext()
                  .getRequestDispatcher("/login.do")
                  .forward(request, response);

            return;
        }

        //end if
        if (acl.isProtectedResource(url)) {

            //get subject
            final String group = (String) hreq.getSession()
                                              .getAttribute("group");

            if (!acl.hasRight(url, group)) {

                config.getServletContext()
                      .getRequestDispatcher("/noRight.do?method=noRight")
                      .forward(request, response);

                return;
            }

            //end if
        }

        //end if
        // Pass control on to the next filter
        chain.doFilter(request, response);
    }

    /**
     * Place this filter into service. Read acl configuration from file
     *
     * @param filterConfig The filter configuration object
     * @exception ServletException error
     */
    public final void init(final FilterConfig filterConfig)
        throws ServletException {

        config = filterConfig;

        ServletContext context = filterConfig.getServletContext();
        acl = (Acl) Global.getInstance()
                          .getService("acl");
    }
}